Yeah, if they were going to do it, they'd be doing it, not talking about it.
Joe Biden's job is to worry about it anyway. You have to have contingencies for when your enemy does something incredibly stupid.
But this isn't aimed at Biden. It's aimed at the rank-and-file in the West, part of the firehose of falsehoods that the Russians use to confuse and disorient. They don't have any particular goal, just hoping that it will cause us to make some kind of mistake that they'll take advantage of.
That would effectively start World War 3 and into unknown territory: full-scale war between multiple nuclear-armed nations.